Auto merge of #110705 - saethlin:ignore-locals-cost, r=cjgillot

Remove the size of locals heuristic in MIR inlining

This heuristic doesn't necessarily correlate to complexity of the MIR Body. In particular, a lot of straight-line code in MIR tends to never reuse a local, even though any optimizer would effectively reuse the storage or just put everything in registers. So it doesn't even necessarily make sense that this would be a stack size heuristic.

So... what happens if we just delete the heuristic? The benchmark suite improves significantly. Less heuristics better?

r? `@cjgillot`

5 files changed, 450 insertions, 82 deletions

diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index 1525933aee3..552bf43329c 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -26,8 +26,6 @@ const CALL_PENALTY: usize = 25;
 const LANDINGPAD_PENALTY: usize = 50;
 const RESUME_PENALTY: usize = 45;
 
-const UNKNOWN_SIZE_COST: usize = 10;
-
 const TOP_DOWN_DEPTH_LIMIT: usize = 5;
 
 pub struct Inline;
@@ -464,12 +462,6 @@ impl<'tcx> Inliner<'tcx> {
             }
         }
 
-        // Count up the cost of local variables and temps, if we know the size
-        // use that, otherwise we use a moderately-large dummy cost.
-        for v in callee_body.vars_and_temps_iter() {
-            checker.visit_local_decl(v, &callee_body.local_decls[v]);
-        }
-
         // Abort if type validation found anything fishy.
         checker.validation?;
 
@@ -764,14 +756,6 @@ impl<'tcx> Inliner<'tcx> {
     }
 }
 
-fn type_size_of<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
-    ty: Ty<'tcx>,
-) -> Option<u64> {
-    tcx.layout_of(param_env.and(ty)).ok().map(|layout| layout.size.bytes())
-}
-
 /// Verify that the callee body is compatible with the caller.
 ///
 /// This visitor mostly computes the inlining cost,
@@ -845,24 +829,6 @@ impl<'tcx> Visitor<'tcx> for CostChecker<'_, 'tcx> {
         self.super_terminator(terminator, location);
     }
 
-    /// Count up the cost of local variables and temps, if we know the size
-    /// use that, otherwise we use a moderately-large dummy cost.
-    fn visit_local_decl(&mut self, local: Local, local_decl: &LocalDecl<'tcx>) {
-        let tcx = self.tcx;
-        let ptr_size = tcx.data_layout.pointer_size.bytes();
-
-        let ty = self.instance.subst_mir(tcx, &local_decl.ty);
-        // Cost of the var is the size in machine-words, if we know
-        // it.
-        if let Some(size) = type_size_of(tcx, self.param_env, ty) {
-            self.cost += ((size + ptr_size - 1) / ptr_size) as usize;
-        } else {
-            self.cost += UNKNOWN_SIZE_COST;
-        }
-
-        self.super_local_decl(local, local_decl)
-    }
-
     /// This method duplicates code from MIR validation in an attempt to detect type mismatches due
     /// to normalization failure.
     fn visit_projection_elem(
diff --git a/tests/mir-opt/inline/unchecked_shifts.unchecked_shl_unsigned_smaller.Inline.diff b/tests/mir-opt/inline/unchecked_shifts.unchecked_shl_unsigned_smaller.Inline.diff
index 473e02f1cb1..d76cd0e2bb8 100644
--- a/tests/mir-opt/inline/unchecked_shifts.unchecked_shl_unsigned_smaller.Inline.diff
+++ b/tests/mir-opt/inline/unchecked_shifts.unchecked_shl_unsigned_smaller.Inline.diff
@@ -12,7 +12,51 @@
 +         debug rhs => _4;                 // in scope 1 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
 +         let mut _5: u16;                 // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
 +         let mut _6: (u32,);              // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         let mut _7: u32;                 // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
 +         scope 2 {
++             scope 3 (inlined core::num::<impl u16>::unchecked_shl::conv) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                 debug x => _7;           // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                 let mut _8: std::option::Option<u16>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                 let mut _9: std::result::Result<u16, std::num::TryFromIntError>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                 scope 4 {
++                     scope 5 (inlined <u32 as TryInto<u16>>::try_into) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                         debug self => _7; // in scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
++                         scope 6 (inlined convert::num::<impl TryFrom<u32> for u16>::try_from) { // at $SRC_DIR/core/src/convert/mod.rs:LL:COL
++                             debug u => _7; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++                             let mut _10: bool; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++                             let mut _11: u32; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++                             let mut _12: u16; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++                         }
++                     }
++                     scope 7 (inlined Result::<u16, TryFromIntError>::ok) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                         debug self => _9; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++                         let mut _13: isize; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++                         let _14: u16;    // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++                         scope 8 {
++                             debug x => _14; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
++                         }
++                     }
++                     scope 9 (inlined #[track_caller] Option::<u16>::unwrap_unchecked) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                         debug self => _8; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++                         let mut _15: &std::option::Option<u16>; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++                         let mut _16: isize; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++                         scope 10 {
++                             debug val => _5; // in scope 10 at $SRC_DIR/core/src/option.rs:LL:COL
++                         }
++                         scope 11 {
++                             scope 13 (inlined unreachable_unchecked) { // at $SRC_DIR/core/src/option.rs:LL:COL
++                                 scope 14 {
++                                     scope 15 (inlined unreachable_unchecked::runtime) { // at $SRC_DIR/core/src/intrinsics.rs:LL:COL
++                                     }
++                                 }
++                             }
++                         }
++                         scope 12 (inlined Option::<u16>::is_some) { // at $SRC_DIR/core/src/option.rs:LL:COL
++                             debug self => _15; // in scope 12 at $SRC_DIR/core/src/option.rs:LL:COL
++                         }
++                     }
++                 }
++             }
 +         }
 +     }
   
@@ -22,30 +66,87 @@
           StorageLive(_4);                 // scope 0 at $DIR/unchecked_shifts.rs:+1:21: +1:22
           _4 = _2;                         // scope 0 at $DIR/unchecked_shifts.rs:+1:21: +1:22
 -         _0 = core::num::<impl u16>::unchecked_shl(move _3, move _4) -> bb1; // scope 0 at $DIR/unchecked_shifts.rs:+1:5: +1:23
+-                                          // mir::Constant
+-                                          // + span: $DIR/unchecked_shifts.rs:11:7: 11:20
+-                                          // + literal: Const { ty: unsafe fn(u16, u32) -> u16 {core::num::<impl u16>::unchecked_shl}, val: Value(<ZST>) }
 +         StorageLive(_5);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
 +         StorageLive(_6);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
 +         _6 = (_4,);                      // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-+         _5 = core::num::<impl u16>::unchecked_shl::conv(move (_6.0: u32)) -> bb1; // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-                                           // mir::Constant
--                                          // + span: $DIR/unchecked_shifts.rs:11:7: 11:20
--                                          // + literal: Const { ty: unsafe fn(u16, u32) -> u16 {core::num::<impl u16>::unchecked_shl}, val: Value(<ZST>) }
-+                                          // + span: $SRC_DIR/core/src/num/mod.rs:LL:COL
-+                                          // + literal: Const { ty: fn(u32) -> u16 {core::num::<impl u16>::unchecked_shl::conv}, val: Value(<ZST>) }
++         StorageLive(_7);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         _7 = move (_6.0: u32);           // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageLive(_8);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageLive(_9);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageLive(_10);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         StorageLive(_11);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         _11 = const 65535_u32;           // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         _10 = Gt(_7, move _11);          // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         StorageDead(_11);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         switchInt(move _10) -> [0: bb3, otherwise: bb2]; // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
       }
   
       bb1: {
-+         StorageDead(_6);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-+         _0 = unchecked_shl::<u16>(_3, move _5) -> [return: bb2, unwind unreachable]; // scope 2 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
-+                                          // mir::Constant
-+                                          // + span: $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
-+                                          // + literal: Const { ty: unsafe extern "rust-intrinsic" fn(u16, u16) -> u16 {unchecked_shl::<u16>}, val: Value(<ZST>) }
-+     }
-+ 
-+     bb2: {
 +         StorageDead(_5);                 // scope 2 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
           StorageDead(_4);                 // scope 0 at $DIR/unchecked_shifts.rs:+1:22: +1:23
           StorageDead(_3);                 // scope 0 at $DIR/unchecked_shifts.rs:+1:22: +1:23
           return;                          // scope 0 at $DIR/unchecked_shifts.rs:+2:2: +2:2
++     }
++ 
++     bb2: {
++         _9 = Result::<u16, TryFromIntError>::Err(const TryFromIntError(())); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++                                          // mir::Constant
++                                          // + span: no-location
++                                          // + literal: Const { ty: TryFromIntError, val: Value(<ZST>) }
++         goto -> bb4;                     // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++     }
++ 
++     bb3: {
++         StorageLive(_12);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         _12 = _7 as u16 (IntToInt);      // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         _9 = Result::<u16, TryFromIntError>::Ok(move _12); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         StorageDead(_12);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         goto -> bb4;                     // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++     }
++ 
++     bb4: {
++         StorageDead(_10);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         StorageLive(_14);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         _13 = discriminant(_9);          // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++         switchInt(move _13) -> [0: bb7, 1: bb5, otherwise: bb6]; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++     }
++ 
++     bb5: {
++         _8 = Option::<u16>::None;        // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++         goto -> bb8;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++     }
++ 
++     bb6: {
++         unreachable;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++     }
++ 
++     bb7: {
++         _14 = move ((_9 as Ok).0: u16);  // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++         _8 = Option::<u16>::Some(move _14); // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
++         goto -> bb8;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++     }
++ 
++     bb8: {
++         StorageDead(_14);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageDead(_9);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageLive(_15);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         _16 = discriminant(_8);          // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++         switchInt(move _16) -> [1: bb9, otherwise: bb6]; // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++     }
++ 
++     bb9: {
++         _5 = move ((_8 as Some).0: u16); // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++         StorageDead(_15);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageDead(_8);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageDead(_7);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageDead(_6);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         _0 = unchecked_shl::<u16>(_3, move _5) -> [return: bb1, unwind unreachable]; // scope 2 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
++                                          // mir::Constant
++                                          // + span: $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
++                                          // + literal: Const { ty: unsafe extern "rust-intrinsic" fn(u16, u16) -> u16 {unchecked_shl::<u16>}, val: Value(<ZST>) }
       }
   }
   
diff --git a/tests/mir-opt/inline/unchecked_shifts.unchecked_shl_unsigned_smaller.PreCodegen.after.mir b/tests/mir-opt/inline/unchecked_shifts.unchecked_shl_unsigned_smaller.PreCodegen.after.mir
index 9b7b11ef659..3c175ed1504 100644
--- a/tests/mir-opt/inline/unchecked_shifts.unchecked_shl_unsigned_smaller.PreCodegen.after.mir
+++ b/tests/mir-opt/inline/unchecked_shifts.unchecked_shl_unsigned_smaller.PreCodegen.after.mir
@@ -9,7 +9,51 @@ fn unchecked_shl_unsigned_smaller(_1: u16, _2: u32) -> u16 {
         debug rhs => _2;                 // in scope 1 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
         let mut _3: u16;                 // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
         let mut _4: (u32,);              // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        let mut _5: u32;                 // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
         scope 2 {
+            scope 3 (inlined core::num::<impl u16>::unchecked_shl::conv) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                debug x => _5;           // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                let mut _6: std::option::Option<u16>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                let mut _7: std::result::Result<u16, std::num::TryFromIntError>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                scope 4 {
+                    scope 5 (inlined <u32 as TryInto<u16>>::try_into) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                        debug self => _5; // in scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
+                        scope 6 (inlined convert::num::<impl TryFrom<u32> for u16>::try_from) { // at $SRC_DIR/core/src/convert/mod.rs:LL:COL
+                            debug u => _5; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+                            let mut _8: bool; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+                            let mut _9: u32; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+                            let mut _10: u16; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+                        }
+                    }
+                    scope 7 (inlined Result::<u16, TryFromIntError>::ok) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                        debug self => _7; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+                        let mut _11: isize; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+                        let _12: u16;    // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+                        scope 8 {
+                            debug x => _12; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
+                        }
+                    }
+                    scope 9 (inlined #[track_caller] Option::<u16>::unwrap_unchecked) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                        debug self => _6; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+                        let mut _13: &std::option::Option<u16>; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+                        let mut _14: isize; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+                        scope 10 {
+                            debug val => _3; // in scope 10 at $SRC_DIR/core/src/option.rs:LL:COL
+                        }
+                        scope 11 {
+                            scope 13 (inlined unreachable_unchecked) { // at $SRC_DIR/core/src/option.rs:LL:COL
+                                scope 14 {
+                                    scope 15 (inlined unreachable_unchecked::runtime) { // at $SRC_DIR/core/src/intrinsics.rs:LL:COL
+                                    }
+                                }
+                            }
+                        }
+                        scope 12 (inlined Option::<u16>::is_some) { // at $SRC_DIR/core/src/option.rs:LL:COL
+                            debug self => _13; // in scope 12 at $SRC_DIR/core/src/option.rs:LL:COL
+                        }
+                    }
+                }
+            }
         }
     }
 
@@ -17,22 +61,78 @@ fn unchecked_shl_unsigned_smaller(_1: u16, _2: u32) -> u16 {
         StorageLive(_3);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
         StorageLive(_4);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
         _4 = (_2,);                      // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-        _3 = core::num::<impl u16>::unchecked_shl::conv(move (_4.0: u32)) -> bb1; // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-                                         // mir::Constant
-                                         // + span: $SRC_DIR/core/src/num/mod.rs:LL:COL
-                                         // + literal: Const { ty: fn(u32) -> u16 {core::num::<impl u16>::unchecked_shl::conv}, val: Value(<ZST>) }
+        StorageLive(_5);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        _5 = move (_4.0: u32);           // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageLive(_6);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageLive(_7);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageLive(_8);                 // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        StorageLive(_9);                 // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        _9 = const 65535_u32;            // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        _8 = Gt(_5, move _9);            // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        StorageDead(_9);                 // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        switchInt(move _8) -> [0: bb3, otherwise: bb2]; // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
     }
 
     bb1: {
+        StorageDead(_3);                 // scope 2 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+        return;                          // scope 0 at $DIR/unchecked_shifts.rs:+2:2: +2:2
+    }
+
+    bb2: {
+        _7 = Result::<u16, TryFromIntError>::Err(const TryFromIntError(())); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+                                         // mir::Constant
+                                         // + span: no-location
+                                         // + literal: Const { ty: TryFromIntError, val: Value(<ZST>) }
+        goto -> bb4;                     // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+    }
+
+    bb3: {
+        StorageLive(_10);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        _10 = _5 as u16 (IntToInt);      // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        _7 = Result::<u16, TryFromIntError>::Ok(move _10); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        StorageDead(_10);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        goto -> bb4;                     // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+    }
+
+    bb4: {
+        StorageDead(_8);                 // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        StorageLive(_12);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        _11 = discriminant(_7);          // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+        switchInt(move _11) -> [0: bb7, 1: bb5, otherwise: bb6]; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+    }
+
+    bb5: {
+        _6 = Option::<u16>::None;        // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+        goto -> bb8;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+    }
+
+    bb6: {
+        unreachable;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+    }
+
+    bb7: {
+        _12 = move ((_7 as Ok).0: u16);  // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+        _6 = Option::<u16>::Some(move _12); // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
+        goto -> bb8;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+    }
+
+    bb8: {
+        StorageDead(_12);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageDead(_7);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageLive(_13);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        _14 = discriminant(_6);          // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+        switchInt(move _14) -> [1: bb9, otherwise: bb6]; // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+    }
+
+    bb9: {
+        _3 = move ((_6 as Some).0: u16); // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+        StorageDead(_13);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageDead(_6);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageDead(_5);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
         StorageDead(_4);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-        _0 = unchecked_shl::<u16>(_1, move _3) -> [return: bb2, unwind unreachable]; // scope 2 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
+        _0 = unchecked_shl::<u16>(_1, move _3) -> [return: bb1, unwind unreachable]; // scope 2 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
                                          // + literal: Const { ty: unsafe extern "rust-intrinsic" fn(u16, u16) -> u16 {unchecked_shl::<u16>}, val: Value(<ZST>) }
     }
-
-    bb2: {
-        StorageDead(_3);                 // scope 2 at $SRC_DIR/core/src/num/uint_macros.rs:LL:COL
-        return;                          // scope 0 at $DIR/unchecked_shifts.rs:+2:2: +2:2
-    }
 }
diff --git a/tests/mir-opt/inline/unchecked_shifts.unchecked_shr_signed_smaller.Inline.diff b/tests/mir-opt/inline/unchecked_shifts.unchecked_shr_signed_smaller.Inline.diff
index 9638ddda46b..f3d3e6090bb 100644
--- a/tests/mir-opt/inline/unchecked_shifts.unchecked_shr_signed_smaller.Inline.diff
+++ b/tests/mir-opt/inline/unchecked_shifts.unchecked_shr_signed_smaller.Inline.diff
@@ -12,7 +12,51 @@
 +         debug rhs => _4;                 // in scope 1 at $SRC_DIR/core/src/num/int_macros.rs:LL:COL
 +         let mut _5: i16;                 // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
 +         let mut _6: (u32,);              // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         let mut _7: u32;                 // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
 +         scope 2 {
++             scope 3 (inlined core::num::<impl i16>::unchecked_shr::conv) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                 debug x => _7;           // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                 let mut _8: std::option::Option<i16>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                 let mut _9: std::result::Result<i16, std::num::TryFromIntError>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                 scope 4 {
++                     scope 5 (inlined <u32 as TryInto<i16>>::try_into) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                         debug self => _7; // in scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
++                         scope 6 (inlined convert::num::<impl TryFrom<u32> for i16>::try_from) { // at $SRC_DIR/core/src/convert/mod.rs:LL:COL
++                             debug u => _7; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++                             let mut _10: bool; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++                             let mut _11: u32; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++                             let mut _12: i16; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++                         }
++                     }
++                     scope 7 (inlined Result::<i16, TryFromIntError>::ok) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                         debug self => _9; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++                         let mut _13: isize; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++                         let _14: i16;    // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++                         scope 8 {
++                             debug x => _14; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
++                         }
++                     }
++                     scope 9 (inlined #[track_caller] Option::<i16>::unwrap_unchecked) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
++                         debug self => _8; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++                         let mut _15: &std::option::Option<i16>; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++                         let mut _16: isize; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++                         scope 10 {
++                             debug val => _5; // in scope 10 at $SRC_DIR/core/src/option.rs:LL:COL
++                         }
++                         scope 11 {
++                             scope 13 (inlined unreachable_unchecked) { // at $SRC_DIR/core/src/option.rs:LL:COL
++                                 scope 14 {
++                                     scope 15 (inlined unreachable_unchecked::runtime) { // at $SRC_DIR/core/src/intrinsics.rs:LL:COL
++                                     }
++                                 }
++                             }
++                         }
++                         scope 12 (inlined Option::<i16>::is_some) { // at $SRC_DIR/core/src/option.rs:LL:COL
++                             debug self => _15; // in scope 12 at $SRC_DIR/core/src/option.rs:LL:COL
++                         }
++                     }
++                 }
++             }
 +         }
 +     }
   
@@ -22,30 +66,87 @@
           StorageLive(_4);                 // scope 0 at $DIR/unchecked_shifts.rs:+1:21: +1:22
           _4 = _2;                         // scope 0 at $DIR/unchecked_shifts.rs:+1:21: +1:22
 -         _0 = core::num::<impl i16>::unchecked_shr(move _3, move _4) -> bb1; // scope 0 at $DIR/unchecked_shifts.rs:+1:5: +1:23
+-                                          // mir::Constant
+-                                          // + span: $DIR/unchecked_shifts.rs:17:7: 17:20
+-                                          // + literal: Const { ty: unsafe fn(i16, u32) -> i16 {core::num::<impl i16>::unchecked_shr}, val: Value(<ZST>) }
 +         StorageLive(_5);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
 +         StorageLive(_6);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
 +         _6 = (_4,);                      // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-+         _5 = core::num::<impl i16>::unchecked_shr::conv(move (_6.0: u32)) -> bb1; // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-                                           // mir::Constant
--                                          // + span: $DIR/unchecked_shifts.rs:17:7: 17:20
--                                          // + literal: Const { ty: unsafe fn(i16, u32) -> i16 {core::num::<impl i16>::unchecked_shr}, val: Value(<ZST>) }
-+                                          // + span: $SRC_DIR/core/src/num/mod.rs:LL:COL
-+                                          // + literal: Const { ty: fn(u32) -> i16 {core::num::<impl i16>::unchecked_shr::conv}, val: Value(<ZST>) }
++         StorageLive(_7);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         _7 = move (_6.0: u32);           // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageLive(_8);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageLive(_9);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageLive(_10);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         StorageLive(_11);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         _11 = const 32767_u32;           // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         _10 = Gt(_7, move _11);          // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         StorageDead(_11);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         switchInt(move _10) -> [0: bb3, otherwise: bb2]; // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
       }
   
       bb1: {
-+         StorageDead(_6);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-+         _0 = unchecked_shr::<i16>(_3, move _5) -> [return: bb2, unwind unreachable]; // scope 2 at $SRC_DIR/core/src/num/int_macros.rs:LL:COL
-+                                          // mir::Constant
-+                                          // + span: $SRC_DIR/core/src/num/int_macros.rs:LL:COL
-+                                          // + literal: Const { ty: unsafe extern "rust-intrinsic" fn(i16, i16) -> i16 {unchecked_shr::<i16>}, val: Value(<ZST>) }
-+     }
-+ 
-+     bb2: {
 +         StorageDead(_5);                 // scope 2 at $SRC_DIR/core/src/num/int_macros.rs:LL:COL
           StorageDead(_4);                 // scope 0 at $DIR/unchecked_shifts.rs:+1:22: +1:23
           StorageDead(_3);                 // scope 0 at $DIR/unchecked_shifts.rs:+1:22: +1:23
           return;                          // scope 0 at $DIR/unchecked_shifts.rs:+2:2: +2:2
++     }
++ 
++     bb2: {
++         _9 = Result::<i16, TryFromIntError>::Err(const TryFromIntError(())); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++                                          // mir::Constant
++                                          // + span: no-location
++                                          // + literal: Const { ty: TryFromIntError, val: Value(<ZST>) }
++         goto -> bb4;                     // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++     }
++ 
++     bb3: {
++         StorageLive(_12);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         _12 = _7 as i16 (IntToInt);      // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         _9 = Result::<i16, TryFromIntError>::Ok(move _12); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         StorageDead(_12);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         goto -> bb4;                     // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++     }
++ 
++     bb4: {
++         StorageDead(_10);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
++         StorageLive(_14);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         _13 = discriminant(_9);          // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++         switchInt(move _13) -> [0: bb7, 1: bb5, otherwise: bb6]; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++     }
++ 
++     bb5: {
++         _8 = Option::<i16>::None;        // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++         goto -> bb8;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++     }
++ 
++     bb6: {
++         unreachable;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++     }
++ 
++     bb7: {
++         _14 = move ((_9 as Ok).0: i16);  // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++         _8 = Option::<i16>::Some(move _14); // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
++         goto -> bb8;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
++     }
++ 
++     bb8: {
++         StorageDead(_14);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageDead(_9);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageLive(_15);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         _16 = discriminant(_8);          // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++         switchInt(move _16) -> [1: bb9, otherwise: bb6]; // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++     }
++ 
++     bb9: {
++         _5 = move ((_8 as Some).0: i16); // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
++         StorageDead(_15);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageDead(_8);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageDead(_7);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         StorageDead(_6);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
++         _0 = unchecked_shr::<i16>(_3, move _5) -> [return: bb1, unwind unreachable]; // scope 2 at $SRC_DIR/core/src/num/int_macros.rs:LL:COL
++                                          // mir::Constant
++                                          // + span: $SRC_DIR/core/src/num/int_macros.rs:LL:COL
++                                          // + literal: Const { ty: unsafe extern "rust-intrinsic" fn(i16, i16) -> i16 {unchecked_shr::<i16>}, val: Value(<ZST>) }
       }
   }
   
diff --git a/tests/mir-opt/inline/unchecked_shifts.unchecked_shr_signed_smaller.PreCodegen.after.mir b/tests/mir-opt/inline/unchecked_shifts.unchecked_shr_signed_smaller.PreCodegen.after.mir
index afe6d08741b..724b3c56723 100644
--- a/tests/mir-opt/inline/unchecked_shifts.unchecked_shr_signed_smaller.PreCodegen.after.mir
+++ b/tests/mir-opt/inline/unchecked_shifts.unchecked_shr_signed_smaller.PreCodegen.after.mir
@@ -9,7 +9,51 @@ fn unchecked_shr_signed_smaller(_1: i16, _2: u32) -> i16 {
         debug rhs => _2;                 // in scope 1 at $SRC_DIR/core/src/num/int_macros.rs:LL:COL
         let mut _3: i16;                 // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
         let mut _4: (u32,);              // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        let mut _5: u32;                 // in scope 1 at $SRC_DIR/core/src/num/mod.rs:LL:COL
         scope 2 {
+            scope 3 (inlined core::num::<impl i16>::unchecked_shr::conv) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                debug x => _5;           // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                let mut _6: std::option::Option<i16>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                let mut _7: std::result::Result<i16, std::num::TryFromIntError>; // in scope 3 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                scope 4 {
+                    scope 5 (inlined <u32 as TryInto<i16>>::try_into) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                        debug self => _5; // in scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
+                        scope 6 (inlined convert::num::<impl TryFrom<u32> for i16>::try_from) { // at $SRC_DIR/core/src/convert/mod.rs:LL:COL
+                            debug u => _5; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+                            let mut _8: bool; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+                            let mut _9: u32; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+                            let mut _10: i16; // in scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+                        }
+                    }
+                    scope 7 (inlined Result::<i16, TryFromIntError>::ok) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                        debug self => _7; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+                        let mut _11: isize; // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+                        let _12: i16;    // in scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+                        scope 8 {
+                            debug x => _12; // in scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
+                        }
+                    }
+                    scope 9 (inlined #[track_caller] Option::<i16>::unwrap_unchecked) { // at $SRC_DIR/core/src/num/mod.rs:LL:COL
+                        debug self => _6; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+                        let mut _13: &std::option::Option<i16>; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+                        let mut _14: isize; // in scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+                        scope 10 {
+                            debug val => _3; // in scope 10 at $SRC_DIR/core/src/option.rs:LL:COL
+                        }
+                        scope 11 {
+                            scope 13 (inlined unreachable_unchecked) { // at $SRC_DIR/core/src/option.rs:LL:COL
+                                scope 14 {
+                                    scope 15 (inlined unreachable_unchecked::runtime) { // at $SRC_DIR/core/src/intrinsics.rs:LL:COL
+                                    }
+                                }
+                            }
+                        }
+                        scope 12 (inlined Option::<i16>::is_some) { // at $SRC_DIR/core/src/option.rs:LL:COL
+                            debug self => _13; // in scope 12 at $SRC_DIR/core/src/option.rs:LL:COL
+                        }
+                    }
+                }
+            }
         }
     }
 
@@ -17,22 +61,78 @@ fn unchecked_shr_signed_smaller(_1: i16, _2: u32) -> i16 {
         StorageLive(_3);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
         StorageLive(_4);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
         _4 = (_2,);                      // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-        _3 = core::num::<impl i16>::unchecked_shr::conv(move (_4.0: u32)) -> bb1; // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-                                         // mir::Constant
-                                         // + span: $SRC_DIR/core/src/num/mod.rs:LL:COL
-                                         // + literal: Const { ty: fn(u32) -> i16 {core::num::<impl i16>::unchecked_shr::conv}, val: Value(<ZST>) }
+        StorageLive(_5);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        _5 = move (_4.0: u32);           // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageLive(_6);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageLive(_7);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageLive(_8);                 // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        StorageLive(_9);                 // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        _9 = const 32767_u32;            // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        _8 = Gt(_5, move _9);            // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        StorageDead(_9);                 // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        switchInt(move _8) -> [0: bb3, otherwise: bb2]; // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
     }
 
     bb1: {
+        StorageDead(_3);                 // scope 2 at $SRC_DIR/core/src/num/int_macros.rs:LL:COL
+        return;                          // scope 0 at $DIR/unchecked_shifts.rs:+2:2: +2:2
+    }
+
+    bb2: {
+        _7 = Result::<i16, TryFromIntError>::Err(const TryFromIntError(())); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+                                         // mir::Constant
+                                         // + span: no-location
+                                         // + literal: Const { ty: TryFromIntError, val: Value(<ZST>) }
+        goto -> bb4;                     // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+    }
+
+    bb3: {
+        StorageLive(_10);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        _10 = _5 as i16 (IntToInt);      // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        _7 = Result::<i16, TryFromIntError>::Ok(move _10); // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        StorageDead(_10);                // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        goto -> bb4;                     // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+    }
+
+    bb4: {
+        StorageDead(_8);                 // scope 6 at $SRC_DIR/core/src/convert/num.rs:LL:COL
+        StorageLive(_12);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        _11 = discriminant(_7);          // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+        switchInt(move _11) -> [0: bb7, 1: bb5, otherwise: bb6]; // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+    }
+
+    bb5: {
+        _6 = Option::<i16>::None;        // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+        goto -> bb8;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+    }
+
+    bb6: {
+        unreachable;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+    }
+
+    bb7: {
+        _12 = move ((_7 as Ok).0: i16);  // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+        _6 = Option::<i16>::Some(move _12); // scope 8 at $SRC_DIR/core/src/result.rs:LL:COL
+        goto -> bb8;                     // scope 7 at $SRC_DIR/core/src/result.rs:LL:COL
+    }
+
+    bb8: {
+        StorageDead(_12);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageDead(_7);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageLive(_13);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        _14 = discriminant(_6);          // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+        switchInt(move _14) -> [1: bb9, otherwise: bb6]; // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+    }
+
+    bb9: {
+        _3 = move ((_6 as Some).0: i16); // scope 9 at $SRC_DIR/core/src/option.rs:LL:COL
+        StorageDead(_13);                // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageDead(_6);                 // scope 4 at $SRC_DIR/core/src/num/mod.rs:LL:COL
+        StorageDead(_5);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
         StorageDead(_4);                 // scope 2 at $SRC_DIR/core/src/num/mod.rs:LL:COL
-        _0 = unchecked_shr::<i16>(_1, move _3) -> [return: bb2, unwind unreachable]; // scope 2 at $SRC_DIR/core/src/num/int_macros.rs:LL:COL
+        _0 = unchecked_shr::<i16>(_1, move _3) -> [return: bb1, unwind unreachable]; // scope 2 at $SRC_DIR/core/src/num/int_macros.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/num/int_macros.rs:LL:COL
                                          // + literal: Const { ty: unsafe extern "rust-intrinsic" fn(i16, i16) -> i16 {unchecked_shr::<i16>}, val: Value(<ZST>) }
     }
-
-    bb2: {
-        StorageDead(_3);                 // scope 2 at $SRC_DIR/core/src/num/int_macros.rs:LL:COL
-        return;                          // scope 0 at $DIR/unchecked_shifts.rs:+2:2: +2:2
-    }
 }